Bug: Hidden clips cross+greyed out thumb sometimes dissapear on mouseover

[Lukas]

When you 'Hide' a clip. It gets a cross and gets greyed out. This is very useful.

There's a bug that makes the feature a bit problematic though:
However, when you hover over the clip, the cross and grey overlay often disappear. Sometimes they re-appear on mouse-over, but dissapear again when the mouse leaves. It's very erratic and unpredictable.